Chromium-plated carbon article



i No Drawing.

s ze-we Patented my 51,1927

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FREDEBICK m. BECKET, OF-NEW YORK, N. Y., ASSIGNORTO ELETRO METALLURGICAL COMIPANY, A. CORPORATION OF WEST VIRGINIA. I

A CHROMIUM-PLATED CARBON ARTICLE.

conductivity, which is often advantageous.

' Graphite is frequently used for molds where i tioned, especially if t rapid cooling of the casting is desired. In the making of toothed cutters from alloys of the cobalt-chromium type, it has been found desirable'to cast the cutter in a sand mold into which there has been set at the point where each tooth will form, a small prism of graphite, called a chill, for the purpose of rapidly cooling the metal at the surface of the tooth, so that the cutting portion of the tooth will have the requisite hardness.

It is found, however, that carbon is considerably attacked by the molten metal when it is used for such urposes as those mene molten material is at an unusually high temperature. surface is eroded by currents of molten material, andlgases are evolved at the surface of the carbon, presumably by reaction be- The carbon Application filed December 1, 1924. Serial No. 753,358.

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tween constituents of the molten material and the carbon, producing blow-holes in casting.

I have found that carbon articles for the uses, referred to are greatly improved by plating them with chromium. The plate may be applied electrolytically, for example, with or wftlrout an underlying plating of copper or c. ner metal. Chromium is hard, has a very high meltmg point, and does. not alloy readily at the temperatures usually encountered in casting the operations. "For these reasons it renders a i carbon article more resistant to wear an t,

erosion, and it tends to obviate gas-produc ing reactions such as would give rise to unsound casting's. A chromium plating favors rapid cooling of the casting, which is desirable in those cases where a carbon mold is used, because the meta-l-to-metal contact .is more intimate and conductsheat more readily than the contact between the molten metal and graphite. The plating is of course in intimate contact with the'body of the mold.

I claim: a b a 1. A chromium-plated carbon article for use in contact with hot molten material.

v2. A chromium-plated graphite chill. Y

In testimony whereof I aflix my signature.

rnnnnmor: M. BECKET. 

